Artillery shell and method of firing thereof

ABSTRACT

The present invention relates to a method and a device for improving—at least in part—the external ballistieds of primarily the type of artillery shells ( 1 ) that are fin-stabilised in their trajectory towards the target and thus have a slipping plastic driving band ( 6 ) which, during firing of the said shell from a designated barrel, constitutes the shell&#39;s direct contact with the inside of the barrel. The problem that it is the function of the present invention to resolve is that the slipping plastic driving band ( 6 ) normally detaches immediately outside the muzzle of the barrel used for firing, thereby leaving an open groove ( 4 ) that causes distrubing turbulence which is detrimental to the flight of the said shell. The solution to the problem herein proposed is based on a ring-shaped spring-loaded device ( 5 ) arranged between the driving band ( 6 ) and the bottom of the driving band groove ( 4 ) and which device is held pressed against the bottom of the said driving band groove as long as the driving band ( 6 ) is in position but as soon as it detaches from the said driving band groove the said device deploys to re-assume a pre-determined original shape which completely fills the driving band groove ( 4 ) up to and level with the outer surface of the shell ( 1 ).

The present invention relates to a method and a device for improving—atleast in part—the external ballistics of primarily the type of artilleryshells that are fin-stabilised in their trajectory towards the targetand thus have a slipping plastic driving band which, during firing froma designated barrel, constitutes the shell's direct contact with theinside of the barrel.

The slipping plastic driving band means that this type of shell exitsthe barrel with a very low rate of spin or no spin at all, whichobviously facilitates the fin stabilisation of the shell which shall beeffected immediately it exits the muzzle by means of deployment of aplurality of fins previously retracted and integrated in the shell. Theplastic driving band is usually so worn out from its severe treatmentduring the shell's passage through the barrel that the remnants of thedriving band break away from their seat around the shell as the shellexits the muzzle of the gun in which it is fired. As soon as the shellhas left the muzzle the well-defined groove in which the slippingplastic driving band was originally seated thus becomes revealed in theotherwise smooth external surface close to the rear face of the shell.

No one has previously paid any attention to the empty driving bandgroove, but now when every means available is being employed in attemptsto increase the range of tube-firing artillery it has been ascertainedthat the empty, sharply-defined driving band groove causes turbulence inthe surrounding atmosphere that cannot be ignored as it has a retarding,disturbing effect on the shell during its trajectory to the target.

The objective of the present invention is to resolve this problem byoffering a method and a device which, without interfering with thefunctioning of the slipping driving band, fills the driving band grooveas soon as the remnants of the driving band have detached from the saidgroove, thus enabling elimination of the otherwise disturbing turbulencearound the driving band groove in an effective way.

The fundamental principle for the method as claimed in the presentinvention is an arrangement between the bottom of the driving bandgroove and the slipping driving band incorporating a ring-shaped,spring-loaded device that is initially compressed and which, as long asthe driving band is in position, is held pressed against the bottom ofthe driving band groove by the driving band but which device, as soon asthe driving band or remnants of the driving band have detached from thedriving band groove, deploys and re-assumes a predetermined originalshape that completely fills the driving band groove to be level with theouter surface of the shell.

This fundamental principle provides space for a device comprising anopen first part made of a springback material and arranged in thedriving band groove, and which first part is the same width as the saidgroove and has a length equivalent to the circumference of the shell ata position level with the driving band groove and when in deployed stateforms a circular ring with an open gap between its two ends andcomprises a plurality of identical filler elements made similarly ofspringback material mounted in the said first part and directed indeployed state at the bottom of the driving band groove, which fillerelements are so designed that they can be pressed in against the insideof the said first part at the same time as the first part can beretracted against the bottom of the driving band groove with the ends ofthe said first part overlapping while allowing space outside the saidfirst part in the driving band groove for the actual driving band.

According to a preferred variant of the present invention the fillerelements are designed such that in deployed state they extend from eachattachment point in the said first part in a slight arc in towards thebottom of the driving band groove, which they reach in a mainlytangential direction. This variant provides good centring of the firstdevice so that in deployed state it gives a precise filling out of thedriving band groove.

If all the filler elements are also given such a length and are attachedto the inside of the said first device with such a distance between theattachment points that there is adequate space to accommodate thembetween each other when the said device is retracted around the bottomof the driving band groove one achieves a filler device which, when inretracted state, has a thickness that in principle is only equivalent todouble the thickness of the material of which the first ring-shapeddevice and filler elements are fabricated, and for this purpose it isappropriate to use a titanium-based sheet metal with good shape memory.

Finally, it can also be noted that the combined latent spring force,when the first part of the device is retracted around the bottom of thedriving band groove and its filler elements are retracted against thesaid first part, does not need to be greater than that the said firstpart is held in place by the driving band arranged on top as long as thelatter has not come into use.

The present invention is defined in the subsequent Patent Claims, and isnow described in only slightly more detail with reference to somerelevant figures.

In these figures

FIG. 1 depicts an oblique projection of a fin-stabilised shell equippedwith a filling, as claimed in the present invention, of the shell'sdriving band groove after detachment of the slipping driving band, and

FIG. 2 is a section through the shell at a position level with thedriving band groove with half the driving band illustrated in itsoriginal position, while

FIG. 3 depicts the same section as FIG. 2 but with the driving bandgroove filler as claimed in the present invention fully deployed.

The shell 1 depicted in FIG. 1 is fin-stabilised with six aft fins 2 andis guided in its trajectory by four canards 3. Near the deployed aftfins there is a driving band groove 4 which, in the mode illustrated inFIG. 1, is filled by the device 5 claimed in the present invention.

FIG. 2 shows a section through the shell 1 level with the driving bandgroove 4, in part of which a driving band 6 is illustrated. There is adriving band groove filler 5 compressed under the driving band 6 againstthe bottom of the driving band groove 4. FIG. 3 depicts the driving bandgroove filler 5 in deployed state in which it completely fills thedriving band groove after the driving band has detached from the groove.As shown in FIG. 3 the driving band groove filler 5 consists of an outerring 7 of springback material of the same width as the driving bandgroove and with preferably at least the same length as the circumferenceof the shell 1 at a position level with the driving band groove 4. Aplurality of springback filler elements 8 are arranged inside the outerring 7. When deployed the said elements extend in a slight arc from eachof their attachment points down to a tangency of the bottom of thedriving band groove 4 herein designated 9. The distance 11 between theattachment point in the outer ring 7 of each filler element 8 and theattachment point of the next filler element is such that the length ofeach filler element in compressed state has adequate space between itsown attachment point and the attachment point of the next fillerelement. The design of the filler elements 8 is such that the outer ring7 in deployed state is supported concentrically around the bottom of thedriving band groove 9 precisely level with the outer surface of theshell where the outer ring 7 forms a continuation that spans the fullwidth of the driving band groove. As shown in FIG. 3 the outer ring 7 issomewhat shorter than the fill circumference of the shell, while abridging element 12 attached to one end of the said outer ring coversthe gap between the opposite ends of the said outer ring. The gapbetween the said ends is equal to the difference between thecircumference of the shell and the circumference around the bottom ofthe driving band groove.

1. A method for firing artillery shells, comprising: providing anartillery shell comprising: a driving band groove extending around acircumference of the shell, spring means for filling the driving bandgroove disposed in a compressed state within the driving band groove; anouter ring disposed over the spring means and extending around thedriving band groove; and a driving band disposed over the outer ring;firing the artillery shell from a barrel; and deploying the spring meansas the artillery shell exits a muzzle of the barrel so that the springmeans fills the driving band groove, wherein the spring means remains inthe driving band groove after the artillery shell leaves the barrel. 2.The method of claim 1, wherein the artillery shell comprises: a bridgingclement attached to the outer ring.
 3. The method of claim 1, whereinthe artillery shell comprises: a plurality of fins disposed at a rear ofthe artillery shell.
 4. The method of claim 1, wherein: deploying thespring means deploys the outer ring to a position level with an outersurface of the shell; and the spring means deploys to fill the entiregroove.
 5. The method of claim 1, wherein: the driving band detachesfrom the groove as the artillery shell exits the muzzle.
 6. A method forfiring artillery shells, comprising: providing an artillery shellcomprising: a driving band groove extending around a circumference ofthe shell; a plurality of filler elements disposed in a compressed stateagainst a bottom of the driving band groove; an outer ring disposed overthe plurality of filler elements and extending around the driving bandgroove; and a driving band disposed over the outer ring; firing theartillery shell from a barrel; and deploying the filler elements as theartillery shell exits a muzzle of the barrel so that the plurality offiller elements fill the driving band groove, wherein the plurality offiller elements remain in the driving band groove after the artilleryshell leaves the barrel.
 7. The method of claim 6, wherein the artilleryshell comprises: a bridging element attached to the outer ring.
 8. Themethod of claim 6, wherein the artillery shell comprises: a plurality offins disposed at a rear of the artillery shell.
 9. The method of claim6, wherein: deploying the filler elements deploys the outer ring to aposition level with an outer surface of the shell.
 10. The method ofclaim 6, wherein: the filler elements are attached to the outer ring.11. The method of claim 6, wherein: the driving band detaches from thegroove as the artillery shell exits the muzzle.
 12. An artillery shell,comprising: a driving band groove at a rear of the shell; a driving banddisposed within the driving band groove; a driving band groove fillerdisposed within the driving band groove and comprising a plurality ofspringback filler elements; and an outer ring disposed between thedriving band and the driving band groove filler.
 13. The artillery shellof claim 12, wherein the springback filler elements are initially heldin a compressed state by the driving band.
 14. The artillery shell ofclaim 13, wherein the springback filler elements are held in thecompressed state against a bottom of the driving band groove.
 15. Theartillery shell of claim 13, wherein the outer ring comprises a bridgingelement.
 16. The artillery shell of claim 13, wherein the springbackfiller elements are made from metal and are mounted at a plurality ofattachment points.
 17. A method of firing an artillery shell,comprising: providing an artillery shell within a barrel, the shellhaving a driving band groove, a driving band disposed within the drivingband groove, a driving band groove filler disposed within the drivingband groove, and an outer ring disposed between the driving band and thedriving band groove filler, wherein the driving band contacts the insideof the barrel; and firing the shell from the barrel, wherein the drivingband detaches from the driving band groove after firing from the barrel,end the driving band groove filler deploys to fill the driving bandgroove.
 18. The method of claim 17, wherein the driving band groovefiller comprises a plurality of springback filler elements.
 19. Themethod of claim 18, wherein the springback filler elements are made frommetal aid are initially held in a compressed state by the driving bandagainst a bottom of the driving band groove.
 20. The method of claim 19,wherein the outer ring comprises a bridging element, the outer ringdeploying with the springback filler elements, and the bridging elementcovering an open gap in the outer ring as the springback filler elementsdeploy.